Pollen and fungal remains as environmental indicators in surface sediments of Isla Grande de Tierra del Fuego, southernmost Patagonia

MUSOTTO, L.L.; BIANCHINOTTI, M.V.; BORROMEI, A.M.

PALYNOLOGY

AMER ASSOC STRATIGRAPHIC PALYNOLOGISTS FOUNDATION

Año: 2012 vol. 36 p. 162 - 179

0191-6122

Palynological studies (pollen and fungal remains) have been performed in order to increase knowledge of the relation between the present vegetation and fungal biota. The analysis of modern analogues will help to improve the palaeoenvironmental reconstructions of fossil sequences from Isla Grande de Tierra del Fuego. A total of 24 fungal taxa have been found, described and illustrated for further reference. Surface samples were collected from the different vegetation communities developed in the island: steppe, Nothofagus forest?steppe ecotone and Nothofagusforest. The steppe is characterised by predominance of Poaceae pollen accompanied by Nothofagus pollen (up to 30%) and spores of Glomus sp. In the forest?steppe ecotone the Nothofagus pollen frequencies rise up to 50% along with dwarf shrub heath communities and records of Gaeumannomyces species. In the forest unit, the percentage values of Nothofagus pollen surpass 50%. Among the fungal remains, fructifications of Microthyriaceae anddematiaceous spores such as Alternaria sp., Dictyosporium sp. and Sporidesmium sp. are present in forest samples and may be related to damp environments. Ascospores of the coprophilous Sordaria-type and Sporormiella-type appeared to be of common occurrence and are probably associated with livestock grazing. Fungal remains are very scarce in some of the samples obtained in mire environments. The ecological requirements of some of the fungi identified allowed inferences about local conditions of sampled site. This study showed the palaeoenvironmentalindicator value of fungal components and encourages further investigation of surface samples considering local habitat features to obtain a better understanding of local environmental conditions in the past.